1. Field of the Invention
The present invention relates to a refrigerating machine oil composition. More particularly, it pertains to a refrigerating machine oil composition which exhibits excellent stability, sludge preventive properties and copper-plating preventive properties.
2. Description of Related Art
There have heretofore been employed a variety of refrigerating machine oils as lubricating oils for various refrigerating machines to be used in automobile air conditioners, refrigerators, room air conditioners and the like. Since such refrigerating machine oils are in use for a long period of time, these oils are required to be highly reliable.
However, such various disadvantages are found in the use of the conventional refrigerating machine oils such as the generation of copper plating, unsatisfactory stability, rise in total acid number and sludge formation. In view of the above, there are proposed and used compositions comprising various base oils in various combination with additives.
Nevertheless, it can not be said that any of the above-proposed compositions now in use is satisfactory from the viewpoint of practical application. In particular, importance has been attached to environmental problems in recent years with the result that the use of a specified flon refrigerant was sustained which threatens destruction of the ozone layer. Herein, flon means fluorochlorocarbon, fluorochlorohydrocarbon, fluorohydrocarbon or fluorocarbon. Consequently, some alternative refrigerants have emerged, and thus it is hoped that a refrigerating machine oil well suited to such refrigerants will be developed as early as possible.
The research and development of such refrigerating machine oil, however, are only in the initial stages thus revealing that in actual practice that achievement of such oils is not yet sufficient.
Under such circumstances, intensive research and development were made by the present inventor in order to develop a refrigerating machine oil which is excellent in stability, sludge preventive properties and copper-plating preventive properties, capable of being used with high reliability over a long period of time, and also well suited not only for use with the conventional specified flon refrigerants but also with various alternative refrigerants free from the fear of causing environmental pollution.
As a result, it has been found by the present inventor that the objective performance is satisfied by a composition comprising a base oil blended with a specific epoxy compound. Thus, the present invention has been accomplished on the basis of the above-mentioned finding and information.